The present invention relates to an electric head-rest, particularly for vehicle seats, comprising removeable fastening means, of the standard separation sliding pin type, enabling its mounting on the upper portion of the back-rest of the seat, and associated with at least one electric motor connected on the one hand mechanically to a positioning transmission chain for a cushion holder housing and on the other hand, by an electric connection to control members connected to a current supply associated with said seat, within reach of the hands of its occupant.
Such a head-rest could only include a single electric motor, for example for actuating its position in height; it could however comprise a second motor, for actuating its tilt, by pivoting around a horizontal axis. By motor must be understood, in principle, a motor-potentiometer, the axle of which is coupled to the shaft of the motor so that the voltage available on its slider may provide a memory of the positioning in height or in inclination.
A head-rest of this type (DE-A-3 805 957), is already known of which the motor and the associated members (mechanical transmission and the like) are housed in the back-rest of the seat, the head-rest itself being only constituted by a cushion, provided with its two pins for fitting into the back-rest. The latter hence is heavily equipped, which systematically increases the price of the vehicles and renders the establishment of a system of options more difficult. The option "vehicles with or without electric head-rest" is converted in fact into an option "vehicles with or without specially equipped seat back-rest" (for electrical actuation of the positioning of the head-rest).
It is an object of the present invention to overcome this type of drawback and for this purpose, the head-rest of the general type defined at the beginning will be, in accordance with the present invention, essentially characterized in that each electric motor and the positioning transmission chain which is associated therewith are lodged inside said housing, and wherein said electrical connection ends in a connector adapted to be plugged onto a connection base permanently fixed to said upper portion of the back-rest, the latter only containing the portion of said electrical connection which extends between said base and said actuating members.
Thus, to the contrary of what has been encountered in the prior art mentioned above, it is now the head-rest which comprises the maximum number of members, namely the essential members and the back-rest of the seat, the minimum, namely only the electrical connections indispensable between the connection base and the actuating members. In this way a practically autonomous integral head-rest is obtained, constituting in itself alone an optional module. It is even possible, due to the invention, to contemplate mounting on all vehicules seats of which the back-rest is pre-equipped with these connection bases and electrical connections, their price then only being very little increased with respect to that of ordinary seats. Such back-rests will also enable, by the choice of the customer, to mount thereon either a conventional head-rest, with manual adjustments, or a head-rest in accordance with the invention with electrical adjustments.
From the point of view of construction, a head-rest according to the invention could also be distinguished by the following features of mounting and arrangements: it comprises, slideably mounted on two guide rods fast to said pins, a support base adapted to be fixed in said housing and supporting a first electrical motor for actuating the position in height of said base, and as the case may require its potentiometer.
Said positioning transmission chain comprises a screw-nut system and gears, the shaft of said first motor extending vertically.
This head-rest can also comprise, beneath and fast to said support base, a housing for a second electric motor, of horizontal axis, connected mechanically to said guide rods, which are respectively pivoted on the said pins along a virtual horizontal axis, for controlling the tilt of these rods with respect to said pins.
Advantageously also, the positioning transmission chain between said second electric motor and said rods is of the gear type and is arranged to cause said housing and its contents to pivot with respect to said pins.
Other details and advantages of a head-rest according to the invention will appear on reading the description which is given here below by way of purely non-limiting example, with reference to the single figure of the accompanying drawing.